


Care and Guidance

by crawlycrawlers



Series: Care & Guidance [1]
Category: Undertale (Video Game)
Genre: Ectogenitals, Fingering, First Time, Implied Daddy Kink, Incest, M/M, Oral Sex, Skeleheat, eventual fontfest, now not only implied but actual fontcest, phone sex (kind of??)
Language: English
Status: In-Progress
Published: 2016-03-24
Updated: 2017-01-07
Packaged: 2018-05-28 21:45:28
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 8,378
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6346549
Author URL: https://archiveofourown.org/users/crawlycrawlers/pseuds/crawlycrawlers
Summary: <blockquote class="userstuff">
              <p>Papyrus gets his first heat. Fortunately for him and unfortunately for Sans, Gaster is there to help.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> I have no excuse.
> 
> ¯\\_(ツ)_/¯
> 
> HUGE thanks to both Sizzle and  Eizzy for the last-minute proofreading! You guys ROCK. <3

"hey, old man, you seen papyrus around?"

Gaster raises his head from where he's been bent over the piles of papers scavenged from the depths of Sans's workshop back in Snowdin. "Hmm... no?" He scratches his chin. "I do believe he said something about going to the… movies? With the hu- Frisk. He sounded very excited about it."

"...yeah. they did that. yesterday."

"Oh? Really?" Gaster blinks, looks around - and only then realizes the warm yellow light of the reading lamp has brightened to mid-morning sunlight. It streaks through the window and shines a spotlight on the complex equation he's been lost in. "Oh. It's already morning again...?" Gaster notices Sans's expression and shrugs, a little contrite. "Papyrus has had a busy week; he might be sleeping in."

"ehh... i dunno. he usually doesn't..." Sans frowns and glances up the stairs. "maybe i should -"

”Go check on him?”

Sans shoves his hands deeper into his pockets. "couldn't hurt."

Gaster twirls the pen between his phalanges and sighs. "Sans, you have much too little faith in me."

He's getting the disapproving look again.

”...how d'ya figure that?”

”I did not create him to be frail. From what I've observed, Papyrus is in excellent condition. Your concern has no sound basis.”

For a moment, Sans looks like he wants to say something but in the end he simply rolls his eyes and turns back towards the stairs.

”But if you are so worried, I promise I will go check up on him if he won't come down within the next thirty minutes.”

”...and if something's wrong? you gonna take care of him?”

”Well, as the person responsible for the both of you, I'd like to think I know a thing or two about that. You might have no recollection of it, but I did provide the two of you with excellent care.”

Sans gives him - and his surroundings - a long, meaningful look.

In the past few short weeks Gaster's been reacquainting himself with existing again both he and his work have slowly but steadily started taking over the dining table - within two days of the first papers' appearance, Papyrus had been forced to sweep in and evacuate Pet Rock to where it now sits atop the rickety old table by the sofa.

Apart from that, it's not so bad, really. Not like Sans has much room to talk in the first place, he muses as he takes in the haphazard stacks of reports. And not to even mention- oh! There's that plate of spaghetti Papyrus so kindly left for him the previous night; it'd slipped from his mind entirely! How delightful! He was starting to feel a little peckish... and speaking of; what's propping up his arrangement of pipettes isn't actually a beaker but a half-empty mug of what he thinks is tea...? Now where did that come from, and when...?

….okay. So maybe Sans has a point. That still doesn't mean he's right. From what he understands Sans's memories of him are barely more than vague flashes but Sans should know well enough that he and his sibling will always remain Gaster's top priority.

"You worry too much, Sans. He's fine. Besides, didn't you have your concession stand to attend to... oh, thirty-two minutes ago?"

"eh, good things come to those who wait; don't sweat it, dings. but promise me you'll check up on paps, 'kay?"

Like he'd need to be asked twice. "Of course."

"well then. catch ya later."

And with a loud zap, Sans is gone.

Gaster blinks. Oh, what a show-off, he thinks, fondly, before bending back down to his papers.

~*~

Two hours later he is so completely engulfed by the intricacies of another sprawling theory he does not register the faint creak of a door opening nor the slow, shuffling steps down the stairs. It isn’t until he hears Papyrus's voice, so uncharacteristically subdued, that he starts and turns around to find Papyrus there, standing a few feet from his chair.

"FATHER…? I FEEL... VERY ODD," Papyrus begins. "TOO WARM, AND - I THINK THERE MIGHT BE SOMETHING WRONG WITH ME. MY CONSTITUTION IS DECIDEDLY LESS GREAT THAN USUAL."

He’s shifting his weight from one foot to another, worrying the hem of his pajamas between smooth, delicate phalanges. The shirt has slipped down from one shoulder to reveal the curve of his clavicle. Gaster can't help but feel proud, looking at it. What an amazing job he's done with this one. All those little ridges and dips he'd lovingly crafted together... long months of anticipation just to finally witness his little creation blink open its deep, dark eyes for the very first time... Subject S's excited rattling when he'd finally drained the incubation tube and gathered Subject P into his arms...

"...DOCTOR GASTER?"

Oh... right. Back to the topic at hand. Gaster frowns and looks Papyrus up and down again; this time so his gaze doesn't linger. “Warm? Feverish? Do you feel ill?" Papyrus looks fine, at least, and that is a major relief. He has always been an excellently healthy specimen. It would be unfortunate for him to fall ill now, when they're all finally together again.

"NO... MAYBE? I'M... WARM, AND MY MAGIC IS DOING PECULIAR THINGS." Papyrus wraps his arms around himself, still swaying in place. "I... DO NOT KNOW WHAT TO DO ABOUT IT OR HOW TO MAKE IT STOP."

”But it doesn't hurt? You say peculiar... is it uncomfortable?”

”A LITTLE...? I DON'T KNOW HOW TO DESCRIBE IT PROPERLY, I'VE NEVER QUITE FELT LIKE THIS BEFORE,” Papyrus says, "BECAUSE BOTH MY HEALTH AND MY PHYSIQUE ARE VERY FORMIDABLE! NO AILMENTS DARE BOTHER THE GREAT PAPYRUS!" But then his posture slumps and he relents: “UNTIL NOW. COULD YOU… MAYBE... PLEASE TAKE A LOOK? YOU ARE A DOCTOR…”

He's giving Gaster that wide, pleading look, a faint orange glow across his cheekbones - how could he ever say no?

“Of course I will, Papyrus, you don’t have to be so nervous. Just -” he glances around for a good place ”- sit down on the sofa and show me what's wrong, will you? I promise I will attend to you shortly; I merely need to finish writing this.” He gestures toward the paper he had been scribbling on.

Papyrus nods, and soon Gaster hears him shuffle away, then a soft thud as he settles down to wait.

Deep down - though he would never admit it out loud - he finds Papyrus's respectful apprehension utterly charming: the way he seems both overeager and shy for his attention. It is a stark contrast to how Gaster's eldest behaves. Sans was never one for needless propriety and decorum and the passing of time has not helped matters any, and now... now he's seen too much - been through too much - to fit into those old boxes from the time before. As for Papyrus, where once was easy, enthusiastic physical closeness and familiarity is now this cautious deference for what Papyrus no doubt sees as his previously unknown progenitor finally revealed.

Which... while not a lie, is not the full truth, either. He's not Subject 002-P's father, not in the traditional sense. 001-S and 002-P are not his children.

They are so much more than that.

The most complex, challenging, stunning work he's ever created. His magnum opus.

To call him simply their progenitor is to simplify, to trivialize the enormous amount of work, time, expertise, even parts of his very soul he sacrificed to bring his vision to life. He's their father, their creator, their god - and in turn, they're his pride and joy. And whatever Papyrus or Sans want to call him, he'll gladly accept.

And right now, one of them needs him.

He stacks the papers into a neat pile and pushes them aside, then rises from his chair and turns towards the sofa. ”Now then, Papyrus -”

And stops. And stares.

Papyrus has obeyed him to the letter, is what Gaster notes first. The second is -

Gaster swears in a long, quiet string of garbled almost-words.

There's Papyrus, on the sofa, as he should be, and he's -

He's scooted back so his spine is flush against the back the sofa; his legs are pulled up to his chest so his heels rest on the very edge of the cushions -

The shirt has slipped down further and now it shows not just his clavicle but the rounded end of a humerus and a hint of rib -

And Papyrus has wriggled off his shorts so they stretch taut between his kneecaps, and his entire pelvic girdle shines with thick orange magic that pulsates in a steady rhythm and is now - right before Gaster's wide-open eyes - molding itself and shaping and drawing apart to present him a tight, puffy little slit of an opening -

Papyrus is in heat.

Papyrus, his sweet little boy, his beautiful creation, is in heat.

His first heat, if the magic's intense glow is of any indication.

Usually the house's temperature is perfectly pleasant but right now Gaster's thick white turtleneck is sweltering. Deep in his chest his soul feels suddenly aflame. Hot waves of magic unfold inside him - everything in him is stirring awake to respond to the invitation laid bare before him.

He forces it all down. Takes a deep breath. Tries not to swear again but fails - oh stars. Papyrus.

Papyrus has noticed his expression and looks up at him, unsure. ”OH. IS IT... IS IT SOMETHING BAD?"

"No, no, not at all - it's -" Gaster swallows roughly. "It is the very opposite, Papyrus. It's good. It's very good."

"BUT IT FEELS VERY WEIRD." Papyrus frowns again. "HOW IS IT GOOD?"

"I -" Gaster hesitates. "It's good because... it's natural. It's meant to happen."

"BUT I DON'T THINK ANYTHING LIKE THIS HAS EVER HAPPENED TO SANS? HE'S NEVER SAID ANYTHING..."

"Sans... might've decided to deal with it on his own." Gaster sure hasn't asked. A good opportunity hasn't presented itself yet. "Some monsters prefer to keep it private."

"SHOULD I?"

"That is entirely for you to decide, Papyrus. How do you feel about it?"

"THOROUGHLY BEFUDDLED! AND - AND I STILL DON'T KNOW WHAT 'IT' IS, EXACTLY."

"Ah. It's -" He thinks for a moment, which proves to be an interesting challenge in itself through the haze of lust that keeps insisting he go to Papyrus this instant. "It is your magic's way of saying it is now fully developed and there's enough excess to enable procreation."

Papyrus considers this. "I DO NOT THINK MY CAREER IS YET AT A JUNCTURE WHERE I WOULD FIND THAT DESIRABLE." He looks down again and frowns at the intense glow. "DO I HAVE TO?"

The primal urge to bend Papyrus over the sofa's back is suddenly joined by second, equally compelling need to gather him in his arms and press little kisses all over the crown of his skull.

"Oh, Papyrus - that is only if and when you wish it to happen. Your predicament has other... benefits, as well." Gaster finally trusts his self-control enough to step closer. "When your magic is activated like that, you can make yourself feel very, very good."

Papyrus perks up immediately. "REALLY? WOWIE! ....HOW?"

"There are quite a few different ways, but you can simply start by gently touching yourself, or -"

There's a moment of consideration. Then: "COULD... COULD YOU SHOW ME?"

"Of course I would, Papyrus, but... are you certain you want me to...?"

"PLEASE?"

Papyrus does not have to ask for a third time.

Gaster kneels on the floor before him and reaches up. Papyrus obediently follows his lead and draws his knees closer together so Gaster can easily pull his shorts off the rest of the way. He drops them on the floor then slides his hands up Papyrus's femurs and gently coaxes them open again. So pliable, Gaster thinks. Eagerly - so very eagerly - presenting himself for inspection. Is there anything Papyrus wouldn't let him do...?

”Let's take a look then, shall we?”

He skims his thumbs over Papyrus's iliac crests until his hands meet behind Papyrus's hip bones and then tugs, gently, so that Papyrus slides further down, his lower half now tilted just right, his smooth ivory femurs spread and that pulsing, twitching, dripping core of pure magic on perfect, maddening display.

...oh. Oh. This might've been a bad idea, Gaster thinks faintly as he stares at it.

He possesses an exceptional amount of self-control. He knows that - it's much, much higher than your average monster's. He's a man of rationale and cold logic. For the sake of science he’s vivisected his own soul with barely a flinch.

But even he has his limits.

He thinks he might be fast encountering one.

Gaster can't stop staring. Papyrus is saying something, but the buzz that's taken over his skull is too loud for him to make out what.

The orange magic swirls, beckons him - oh, how he wants to, needs to... how easy it'd be to just take out his cock and push it deep inside, drive himself into that eager heat and force it to yield for him - how it'd tighten around him, how it'd clench and throb - how Papyrus would gasp and moan and beg and cry for ”PLEASE, FATHER, MORE -”

Gaster snaps out of it just as his phalanges brush against the metal of his zipper - but no, he can't. Sans would hate him. Sans would loathe him for taking Papyrus’s first. He's seen how Sans's gaze lingers on Papyrus, how his eyelights dim and his grin deepens when Papyrus bends down to pick up a stray sock. Sans has waited for a long time. It would be cruel to take this from him - from them. And Gaster has to admit there's something poetic about his two perfect little creations joining together for their first time; their souls desperately trying to unite again... his sweet little boys, wild and passionate with their love for each other. He wants to see Papyrus's face as he takes Sans's cock. He wants to see Sans's face when Papyrus first clenches down around him. He wants to see…. but gods, Papyrus is right here, flushed and ready and - the magic is still learning how to keep its form, forming and reforming itself as it waits for someone, something to -

Gaster leans back down and nuzzles against it. Stars above he just wants to bury his face in and never come up for air again.

He can do this. This, and only this. Nothing more. Not until Sans is here, too.

With that firmly in mind he leans in to give that first, quick swipe of tongue across the slit. It's barely enough to even tease but the reaction is instantaneous.

Papyrus gasps; his entire ribcage jolts up as his hips grind down. Beneath Gaster's hands Papyrus's femurs quiver.

There was what felt like buzzing within his skull before - now it's a dull roar.

”My god, Papyrus,” Gaster breathes, ”how did I make you so perfect... your taste... so pure and sweet...”

Papyrus's magic is so desperate it’s dripping, eagerly preparing him for the penetration it craves. Gaster laps at it until the slick sweetness has smeared on his cheeks, down his chin, until he’s dizzy and drunk; then he runs the tip of his tongue right along the edges up to that delightful, tiny bright spot above and flicks at it.

Above him, Papyrus makes keening, hitching little noises. His legs are trembling; every single bone rattles faintly.

"THAT - OH - THAT T-TINGLES... AND - N-NYE...H - COULD YOU... MORE...?"

”Ah, yes... but before we begin in earnest, you should... call Sans,” Gaster says, between long, thorough licks. ”He'd... mmhm... definitely want to be here for this -”

”HNGH! I - FATHER, I - AH - AH -” He's writhing, trying to grab purchase from the worn sofa as Gaster keeps gently teasing his tongue over that spot - ”MY PHONE - IS STILL UPSTAIRS, I -”

Wordlessly and without raising his head from where it's nested between Papyrus's femurs Gaster lifts a hand. A faint blue glow radiates from it, and soon Papyrus's phone comes zipping down and drops gently on the sofa.

“Tell me what do you need, Papyrus,” he murmurs between long, leisure licks, “tell me what you want me to do, I want to help you feel good -”

“I NEED - I WANT - MORE,” Papyrus squirms, tries to draw his legs up to press them together but Gaster tightens his grip and pushes them back down. “I - PLEASE - COULD YOU -” He’s a halting, flustered mess, cheekbones glowing with embarrassment and hands now pressed over his mouth. “- PUT SOMETHING… INSIDE…?”

...Gods.

Gaster hoists Papyrus’s legs so they rest over his shoulders and trails a hand down Papyru’s femur until his fingers come to rest lightly against the very edge of Papyrus’s pelvic bone.

"Call Sans," he orders. His mouth is too dry to say much else. He remains utterly still.

Above him there's tapping, slow beeping, then at last - Sans’s tinny voice coming through.

“oh hi papyrus, what’s up? where are you?”

The tips of Gaster's fingers drag down, across the heated magic. So warm. So willing.

“SANS! ...AH! I’M AT HOME WITH FATHENNGH -”

“...bro?”

Papyrus clutches the phone like a lifeline as he moans. Gaster pushes his finger deeper again and yes, there - he’s found the place that’ll really make his baby boy sing.

“papyrus?!”

”MY MAGIC - OH - THERE WAS SOMETHING WRONG AND I FELT WEIRD BUT FATHER IS HELPING ME NOW AND -”

”Tell him how,” Gaster orders. ”Tell him what I'm doing to you.”

”paps, what? what's going on? everything ok?”

”OH MY GOD - AH - SANS - DON'T WORRY! THE GREAT PAPYRUS IS J-JUST FINE!”

Whatever words Papyrus manages to wring out are punctuated with little gasps. A sign that Gaster's not doing his job well enough - if he were doing this right, his boy would be incoherent.

But doesn't he know just the thing to try and fix that.

"FATHER IS - HE SAID HE'D HELP ME FEEL GOOD AND - OH FATHER PLEASE, YES, PLEASE MORE -!"

"bro, wait, wait, what?"

Gaster pulls away only long enough to scold: "Don't leave your brother hanging, Papyrus. Tell him. Describe it." And then he's diving right back in and back to teasing Papyrus with his tongue, nudging at that spot just above where two of his fingers are now buried.

"FATHER IS LICKING ME! AND - AND - A-AND HE PUT HIS FINGERS INSIDE ME AND -"

The inhale that crackles its way through the receiver is so sharp even Gaster can hear it, clear as day.

"he's doing what now?!"

"AH - BROTHER, IT FEELS SO GOOD AND I FEEL SO H-HOT, SANS, I -"

The phone drops and bounces away but Papyrus is beyond caring. His right hand - the one that just held the phone - is now down between his legs, fist grappling against Gaster's hand as he's desperately pushing it, forcing it down and closer and deeper in a wordless plea.

Gaster is only too happy to oblige. He unfurls one more finger. There's three of them now, steadily pumping into Papyrus with slick, obscene noises - the pressure around them is maddening, so tight and wet and warm - he needs to feel it around his cock soon or he'll go insane - simply licking and lapping at the sweetness is not enough, it's both too much and too little -

”NGH! I - PLEASE -”

\- he reaches out with his one free hand, blindly groping for Papyrus's hand until their phalanges meet and their fingers lace together - Papyrus squeezes back so hard it almost hurts -

“FATH - AH! MH! D-DAD - DADDY PLEASE PLEASE DADDY I -”

Papyrus wails as his magic surges and clamps down around Gaster’s fingers, pulsing and contracting wildly as it sparks into a bursting wildfire of an orgasm. He's a trembling, incoherent mess, shaking all over even as his hips jerk and his soul shines so bright it hurts to look at.

Gaster watches the magic as it twirls around where his digits disappear into Papyrus, keeps his hands still and slowly eases up the pressure of his tongue until it is but feather-light butterfly kisses meant only to catch any stray dribbles of magic - oh, how he's tempted to dip his tongue in to fully sample that exquisite taste, but no. His sweet little Papyrus must be very oversensitive by now; he does not want to push his limits. It's too early for that, yet.

Slowly, bit by bit, Papyrus’s death grip on his wrist slackens. Gaster wants to ask if he’s feeling better now - he glances up. Papyrus’s cheeks are glowing, his entire skull damp, body slumped back against the sofa, his ribs rising and falling with a gentle rattle. His unfocused gaze is directed somewhere up toward the ceiling.

Ah. That is definitely answer enough.

Gaster smiles up at him and nuzzles his cheek against Papyrus's hip. There is something riveting about the smoothness of unmarred young bone against his own cracked, ravaged face - not just the difference in texture but the proof that even when he couldn't be there for them, his boys still managed to pull through whole and fine.

Up on the wall behind them a clock ticks away seconds, minutes; Gaster has no idea how long he remains there, utterly still, gazing at Papyrus, slowly smoothing his thumb over the back of Papyrus's metacarpals as he waits for him to regain himself.

“sure looks like you guys had a great time, huh.”

Gaster and Papyrus both startle and turn towards the doorway.

Sans stands there, leaning against the frame, hands buried deep in pockets, his void-like eyesockets trained on the two of them: Gaster, still on his knees on the floor and Papyrus, sprawled over the sofa cushions. And even though Gaster has known Sans since before Sans even existed - even though he's not the only one Sans is addressing - he can't help but shiver when Sans speaks again in a voice purged of all its usual joviality:

“Y o u  b o t h  b e t t e r  b e  u p  f o r  r o u n d  t w o .”

 


	2. Chapter 2

**Summary for the Chapter:**

> Enter Sans.

**Notes for the Chapter:**

> Thank you so, so much for all the comments on the first chapter! They're the reason I decided to extend this entire thing from a one-shot.
> 
> I'm awfully sorry about how long this took (9 months? Are you kidding me!?) but... here it is. The second part - or more accurately, the first part of what was supposed to be the second part. It got so long I had to split it in two, but I promise the third chapter is coming in a much more timely manner than this one.
> 
> Huge thanks and credit goes to both [TheManicMagician](http://archiveofourown.org/users/TheManicMagician/pseuds/TheManicMagician) and [Undertailsoulsex](https://archiveofourown.org/users/undertailsoulsex/pseuds/undertailsoulsex) for being a great sounding board and for proofreading, respectively. <3

  
  
His phone is ringing.

Sans unburrows his head from the well-worn embrace of his folded arms and groans. Ughh... waking up. What a waste. His dream had been such a good one: laundry day, usually the subject of nightmares, now sweetened by Papyrus flitting about in a short apron and shorter still shorts, pulling at Sans's shirt and insisting it be washed... then a dreamlike shifting and blurring and the two of them suddenly tangled up on Sans's bed and the shirt and apron and pants are gone and instead there's just Papyrus's bare hands against Sans's bare ribs -

Oh yes. Good stuff.

Excellent stuff. 

So rudely interrupted.

Sans digs the phone from his pocket and flips it over. He grins. 'Best bro <3' is calling.

He answers.

He listens.

Very soon after, he teleports.

 

~*~

 

Gaster, the absolute utter fucker. He's got Papyrus spread on the sofa while he himself nests on the floor between his bro's legs and damn if it doesn't look like he's got every intention to gain permanent residence. Got his face, his hands, fingers, everything all up in Papyrus's business and even from the doorway Sans can hear the rhythmic, slick sounds of dear daddy hard at work.

What the...

Magic surges to the tips of his phalanges. His entire left arm burns. How dare he, how dare - Papyrus is -

Papyrus is -

Sans halts.

Papyrus is gasping, whimpering, moaning out loud, and yep, those are his bro’s long, pretty fingers scrabbling against Gaster’s hand, trying to get him deeper and faster and -  whatever -

That’s his bro’s cute little toes curling into the back of Gaster’s coat, that’s his bro’s sweet open thighs spreading further - 

That’s his bro in the throes of a bone fide heat. 

Finally.

Finally!

….and it’s not with him. He’d thought - 

Sans clenches his fists. 

The doorway digs between his shoulder blades, catches against his spine. He’s gonna - he’s not gonna - he’s staring, and - 

Papyrus wails and arches his back. There’s a burst of radiance -  an orange glow washes over the stained excuse of a couch, momentarily softens its faded green to pale gold. It’s there then gone again way too quick; bright and light and alive. Sunshine, even back underground.

Sans watches as Papyrus sinks down into the lumpy cushions and stares up, ribcage heaving as if he's just come back from one of his and Undyne's crazy marathons: flushed, mellowed, radiating contentment so wholeheartedly Sans can't help but creep closer to bask in it.

From the looks of it, Gaster's got the same idea. He remains there on the floor, gazing up at Papyrus like what he's got right now is enough, like this is all he needs from life. It's not like the guys at Grillby's or at the MTT resort who've got half an ear for him, half for his next joke. Those folks maybe listen to him talk about Papyrus but remember only the parts that made them laugh. No, Gaster's got that pensive half-smile, that solemn delight locked firm on his face. He looks like he gets it.

Like he actually, truly gets it.

That makes the two of them.

And that - that is where Sans finally finds his voice. 

"sure looks like you guys had a great time, huh."

He’s not sure what exactly he expected - them to spring guiltily apart, maybe - but no such thing happens.  Suppose he should be glad for that; had the old man had the guts to snatch Papyrus's first then start backpedaling about it right in front of Papyrus... Sans would have to have a chat with him, with his blasters doing the talking. Even at the thought alone his magic tries to once more force its way into solidity. Sans clamps down on it. 

Papyrus's entire skull has suffused with a blush. He's snatched his hand back from Gaster's grasp to splay it over his face. Gaster, in turn, simply leans back and cautiously regards Sans. 

He almost wants to tell him to relax, no need to be so tense... but that would be a lie. He opens his mouth again, and what comes out -

"y o u  b o t h  b e t t e r  b e  u p  f o r  r o u n d  t w o."

Gaster is staring at him, eyelights shrunken pinpricks of pure surprise. Mirroring perfectly what Sans himself must look like. He didn’t mean to say that - he’s not -

Sans clicks his teeth together. He wishes his phone would ring again to wake him up.

“you -”

Papyrus makes a weird hitching noise into his palms. He’s pulling his knees up, closing them together now that he can. There’s the faintest rattle starting up around his shoulders and he moves, just a little, hunching forward into himself -

Sans is next to him in a flash.

Gaster backs off and Sans pays him no further attention as he leans forward, claims Papyrus's shoulder into the cup of his palm, and pulls them both through black nothing and into his bedroom upstairs. The bed's still unmade, the pillows pushed into a fort and the blanket a comfy lump draped over them. Sans gives his bro a push: Papyrus thumps softly onto the thick mattress and jerks his head up to meet Sans's eyes.

"SANS, WHAT -"

"you ok?"

They look at each other: Papyrus rattled by the abrupt shift in surroundings, Sans because - well. Because.

"...YES...?" 

But Papyrus doesn't look very convinced. 

"you sure?" Sans checks him over one more time. Turns out Papyrus's pants got left downstairs. The oversized shirt hangs low, but not low enough to fully cover his pelvis and the... things... happening within. It's proving mighty distracting, how that thing glows and... stuff.

Sans stops looking and stuffs his hands into his pockets. Inside the left one there's a bag of ketchup. He curls his phalanges around it, strokes it up and down until it's all thinned out.

He's aware the thing has a name.

Over the years he's squirreled away some choice reading from the human world. Car magazines to surprise Papyrus whenever he's down, and a couple more of an entirely different kind he's got no intention to share: magazines for when grooming water sausages into hot cats gets old, and thinking about machines or anomalies or missing things hurts, and he'd rather escape into research of an entirely different kind. Many a long afternoon spent like that, with his feet up on the station counter, idly waving on any passersby as he leafs through the glossy pages propped open on his lap.

The best part, though - the best part is there's never just pictures but stories, too. It takes surprisingly little effort to do some basic mental switcheroos while reading: substitute bone for skin, ribs for breasts, Papyrus for whichever name...

"BROTHER?"

Oh yeah. Papyrus.

Sans sits down on the edge of the bed, next to his bro who instinctually shifts to accommodate him. His bro, whose knees keep rubbing against each other, minute and restless, like he's not even aware of doing so. Sans glances down again, gaze drawn by the motion and - a stray dribble of magic has leaked down, left a small darkened patch on the off-white sheet. Sans stares at it. His soul feels like it's seizing up. He swallows.

Papyrus is still watching him. "...ARE YOU OKAY?"

"...yeah."

"GREAT! BUT - YOU LOOK TROUBLED."

Papyrus is right, he is troubled, but right now it's not about that. It's about what he'd walked into, and how to proceed from the feeling of familiar things torn to pieces then scattered around. He wants to wait and let things settle, so he can start sifting through them and figure out how everything fits together again. He knows, though, that he's not the only one whose world has abruptly switched directions. He needs to be sure that even if Papyrus was steered into it, he went willing.

"that thing with the doc, downstairs - he asked you beforehand, right? he didn't just -" He makes a vague waving gesture. "- go for it?"

"OF COURSE HE DID! IT WAS ACTUALLY..." Papyrus shifts. The shirt draws taut against his hip, shows its gently curving edge: a path Sans itches to trace. "I... ASKED HIM TO? I WOKE UP FEELING OFF, AND AT FIRST I ASSUMED IT MUST BE THE AFTEREFFECTS OF YESTERDAY’S VIGOROUS TRAINING SO I TRIED UNDYNE'S METHOD OF OUTRESTING IT! BUT... EVEN AFTER SEVERAL HOURS IT ONLY GOT WORSE... AND I THOUGHT SINCE FATHER IS A DOCTOR HE'D KNOW WHAT TO DO." He’s wringing his hands, looking at Sans from the corner of his eye. "AND HE DID! REALLY WELL, TOO... I HAD NO IDEA..."

A flush re-emerges across Papyrus's cheekbones. Sans tries his best not to think back to the way Papyrus's legs had jostled atop Gaster's shoulders almost as if he were taking something bigger - 

He fails.

"that's... nice, bro, but... why didn't you call me? before?"

It probably shouldn't rankle him as deep as it does, he admits as Papyrus launches into an explanation. 

And yet... 

The bed creaks under him. It shouldn't be that big of a deal. Papyrus seems fine as always. No harm done, right?

And yet.

Papyrus always came to him. Whether it be worry about the day's inauspicious horoscope or weighing future career options he sought Sans out and they figured whatever issue out. Together.

Always.

Except for today.

Sure, it was just a lost coin toss of Gaster being at home and available while Sans wasn't, nothing personal to it, but... if only he hadn't listened to the half-assed reassurances and gone to check up on Papyrus, he'd have found out immediately and things would've folded out entirely different. It would've been just the two of them in the bedroom's cozy darkness: Papyrus, tossing and turning on his bed, too hot for the covers - Sans closing the door behind him and crawling over the bed's front bumper then across the vast soft sheets until his fingers met warm, bare bone. Papyrus startled from his fitful sleep and blinking up at him with those big, black sockets, his mouth curving up to an invitation of a smile -

"- AND I CAME TO THE CONCLUSION HE WOULD HAVE MUCH MORE EXPERTISE ON THE SUBJECT, SO I - SANS?"

Sans snaps back to reality, flinches against the harsh light of the bare overhead bulb. Surreptitiously he wipes his mouth. He's glad Papyrus is too busy fretting to notice - he hates it when Sans gets drool on his sleeves.

"ARE YOU EVEN LISTENING TO ME? YOU KEEP ZONING OUT! FATHER SAID THIS IS AN INDIVIDUALLY AFFECTING CONDITION, BUT I THINK IT MIGHT'VE BECOME CONTAGIOUS... DO YOU REQUIRE FATHER'S HELP, TOO?"

His mouth was full of drool. Now it's all sliding down wrong and he's choking.  

"i'm good, bro, really. honest." 

He tries to draw a calming breath. His throat hurts. His head hurts, too. He doesn't need Gaster's - he doesn't need anybody's help. There's nothing to help. "i'm ok, papyrus. trust me."

"BROTHER..."

Papyrus is looking at him, searching his face - worried he's missed something, worried there's something wrong. He does that a lot. Even now, on the surface. Even now, after Gaster's back and there shouldn't be anything to look for anymore.

People say his bro is oblivious. Self-absorbed, pompous, too proud and too loud. Never to Sans's face, not even to his back, but that stuff has a way of getting back to him all the same: he sees it in the slump of Papyrus's shoulders, and in how much it takes from him to square them back up. 

People, Sans thinks fiercely, know jack shit about Papyrus.

“ARE… ARE YOU MAD?” Papyrus clasps his hands together. “THAT I DID THAT WITH FATHER?”

“i -” Of course not is what he wants to say, what the autopilot insists on, but…

...is he mad?

The room’s air is still and heavy, lived-in just the way he likes it. The sheets are soft and mostly dry. Papyrus’s breathing has calmed down, steadied into a soothing soft backbeat.

What is he feeling?

Numb. Warm. A little uncomfortable and a lot bothered - god, the memory of Papyrus’s head thrown back and hips undulating  -

Their _ father _ kneeling between those legs. 

Their creator, Sans knows. An architect, a mason, all those distant, dispassionate words, but also the one who dried his newly-awakened body off and showed him how to eat and taught him how to read -

Sans never called him father. But they both knew it.

And then Papyrus came along, and he threw that word around freely, and wasn’t that supposed to mean something, draw lines, create boundaries?

Does it make him a hypocrite if he’s not applying the same to him and Papyrus? They call themselves brothers. Yet somehow the word never feels like it’s pushing anything in-between them - the opposite. They’re brothers, but at the same time, they just… are. With each other. 

Papyrus had simply applied that same logic to Gaster, too. Sans can’t fault him for that. 

“i’m not mad,” he decides. “just… thrown.”

“WILL YOU LAND SOON?”

He chuckles. “guess i’ll have to. i’m not you.”

Papyrus nyeh-heh-hehs softly.

“but while things are still in the air…”

He keeps getting pulled back to how Papyrus looked like, opening himself to and for Gaster, but there’s something else in his mind too, engraved sharp-edged and cold: how Papyrus and Gaster’s hands were laced together and gripping tight. So tight he thinks there can’t have been room for anything else.

That - he’d be mad about that.

He leans over and bumps his shoulder against Papyrus's arm. Papyrus presses back, and turns his face toward him. Their gazes catch. Hold.

"i know i don't always tell you as much as i should," Sans begins.

"YOU NEVER DO!"

"but i..."

He keeps thinking about the glow, and Papyrus, and Papyrus with Gaster - the bedsprings creak as he shifts closer again.

"i'm kinda..."

Now they're flush from arm to thigh, warm against one another. Papyrus smells faintly of milk and soap and sweat, and Sans fights the urge to press his face into his shoulder to breathe it in. Instead he reaches out. Clasps his hands over the sides of Papyrus's skull. Slides a thumb into the hollow under Papyrus's left cheekbone. It fits perfect.

Papyrus looks at him, curious. "SANS...?"

"i really wanted to, for a long time now, but you weren’t ready, so -"

And he pulls Papyrus down, draws him toward him and to him and closer, closer... Papyrus's pearly-white teeth are so near to Sans's own that Sans not sees but feels the faint trembling of his brother's jaw. He barely has the time to marvel at its curve against his fingers before at last, at long last, he bridges that tiny remaining gap and there's a faint clink as their teeth connect.

Papyrus makes a muffled, surprised noise. But only a fleeting one; soon his mouth parts. and warm magic solidifies against Sans's tongue. It presses against him, soft and tentative, as Papyrus tests what to do with it. He's closed his eyes, furrowed his brow. Sans watches, spellbound, as all the familiar signs of Papyrus trying to figure out something important flit across his face before all uncertainty finally melts into delight.

"BROTHER..."

Sans grips Papyrus's skull harder, kisses him deeper. Their teeth nick and click against each other, the ebb and flow of it so sweet and slow and thorough it pulls them along and under. They move together; Papyrus's hands coming up to grip his jacket, to close around his shoulders, to get him closer still -

His legs are moving too, thighs folding open for Sans to settle in between. And he does.  He pushes Papyrus down on his back and goes after, climbs up onto his knees -

Somewhere behind him, the bedroom door opens.

It's hard to tell, being so focused on his brother's breathy little moans and the insistent long fingers grasping at his back, but Sans is pretty sure the sound that just escaped his mouth was a legit snarl. He turns to look.

Gaster's all cool and business as usual as he steps inside the room. He doesn't even ask for permission. Still, it's not quite the confident demeanor he usually employs: there's some question mixed in with the usual statement. Nor does he leave the general vicinity of the doorway, which is good. Means he knows his presence isn't exactly welcome at the moment.

He still tries, though.

"Sans, I -"

"bugger off, me 'n' papyrus are busy."

It ends up a double-edged sword. Gaster sure shuts up, but Papyrus also frowns and draws away.

"BROTHER! THAT WAS RUDE."

Sans shrugs. "he'll live." He goes chasing after Papyrus's mouth, but as it is stubbornly being moved out of his reach, he latches onto a bit of clavicle instead. If happy had a taste, this'd be it, he thinks.

"Sans, please.  There is no reason for trying to antagonize me. I am sorry if you feel I've overstepped my bounds -"

"no shit."

"- but your brother did come to me first."

"you could've said no." 

"That's - fair enough. I understand why you're upset." He still doesn’t have the decency to look even fleetingly guilty. "But I assure you, had you been put in my place -"

"yeah. had i." By now the entire curve of bone is slick with drool. Sans tests it with his teeth. Beneath him, Papyrus whimpers.

"SANS -"

Gaster won't take the hint. "You were invited to join us. Implicitly."

"not right away, and you shoulda sat on your hands until -"

There are hands pushing his shoulders. Papyrus rolls him to the side and struggles upright. Reluctantly, Sans follows. Flat on his back, as great a place as that is, is not the way he wants to have this conversation.

"WHY?" Papyrus asks. "YOU SAID YOU WEREN’T MAD.” He's perched at the edge of the bed, looking from Sans to Gaster and back again. "WHY SHOULD FATHER HAVE SAID NO? AND WHY ARE YOU TALKING ABOUT ME AS IF I WEREN'T SITTING RIGHT HERE. THAT'S BAD MANNERS."

"...sorry, bro. but - this is between me and him." He glances towards Gaster, who's standing still across the room. 

"BUT... IT HAS TO DO WITH ME," Papyrus says. "DOESN'T IT?"

"Your brother is right, Sans. Do not deny him his agency in this."

He scoffs. "informed agency, i won't, but somehow i doubt you stopped for a presentation."

"THERE'S A PRESENTATION?"

"Papyrus is perfectly capable of making his own choices. Besides -" And at last, Gaster falters, even if for just a blink. "He enjoyed himself. Didn't you?"

"IT WAS FUN!"

Gaster spreads his arms.  _ See? _

Next to him, Papyrus is aglow with a blush and back to rubbing his knees together, and Sans so badly wants to get to that, but -

"you're making it too simple."

"And you're being obstinate. I understand your reservations, I truly do -"

"in theory, maybe.”

"- but you shouldn't let any preconceived societal notions curb you from a desired course of action no matter how unprecedented or unconventional -"

Had he been like this before, too? Maybe it'd been a blessing in disguise, Sans getting the reins of raising Papyrus. Gods.

"that's just carte blanche for being amoral. no thanks."

Gaster's mouth tightens. He's standing up to his full height, which is a pretty considerable one. Papyrus got some of the height and a similar great set of shoulders, but even with him it's still clear they're both mere shadows of the original.

"I was not speaking in a general sense but within this specific instance."

"sounded pretty general to me."

Gaster crosses his arms. "Yet going by what I walked in on - it's fine if it's with you?"

Hell yeah it is, Sans wants to say - Papyrus went down for him like hay for harvest, spread like a buffet. He hadn't even had to ask, not really, but had there been any doubt lurking about he would've paused and asked, and were it a no, he would've stopped. Of all the possible scenarios he's entertained over the years, that part is one that never changes. 

"i know how to keep things under control."

"You feel like you can't trust me."

"trust you?" Sans chuckles. It's a mirthless sound. "we barely even know you."

They stare at each other.

"I..." Gaster goes quiet. "Not by my choice," he says, after a long pause.

"Never by my choice."

Silence hangs over the room. Sans slouches down and kicks his heels against the bed's side. That... might've been a bit below the belt, but it's out there now. No take-backsies. He shoves his hands into his pockets.  The ketchup packet is still there. He wants to rip it open, but things are messy enough as it is so instead he makes do with pushing his heels into the mattress until he's digging against the coiled springs within.

He can't remember most of the accident. Just vague flashes of Gaster telling him, over and over, how Sans’s misgivings were unfounded and how perfectly safe it'd be, and -

_ Trust me, Sans. _

\-  well. See where it got them.

Next to him, Papyrus is picking at the hem of his shirt. His shoulders are hunched, legs pressed together. He's looking down at his hands. Frowning. 

"FATHER," he begins. "OF - OF COURSE IT WASN'T BY CHOICE!" He's trying to turn that frown upside down. Succeeds, kinda - the smile wavers, hovers somewhere on the halfway mark. "NEITHER OF US WOULD EVER THINK THAT THE... ACCIDENT..." He falters, quickly glances down again. Then he sets his jaw and picks back up. "WAS ANYTHING BUT ACCIDENTAL! IF YOU'D KNOWN WHAT IT COULD CAUSE, YOU WOULDN'T HAVE EVER..."

Not very subtly, he nudges Sans.

"...RIGHT, BROTHER?"

Sans slides down further. Papyrus has no memory of it. 

"...yeah," he says. "he’s way too smart for that."

Papyrus looks proudly at Sans, then Gaster, whose mouth tightens yet he doesn't say anything. Sans refuses to even begin deciphering his meticulously blank expression.

"SO WILL YOU PLEASE STOP SCOWLING? FATHER WAS MERELY HELPING ME. AFTER I ASKED."

"sure was, wasn't he." Pretty damn close to helping himself, too. The bastard.

"AND I... REALLY LIKED IT..." The sheets rustle. Papyrus has gone back to shifting in place. "I WISH I'D KNOWN ABOUT IT ALL BEFOREHAND... YOU SHOULD'VE TOLD ME, BROTHER!"

The floor is fascinating. The dust on the cheap carpeting has already begun to form layers, like rock mantles piling over one another, each its own piece of history. Sans clears his throat. "ehh, y'know, i figured, nowadays with the undernet and all, you know, you do like your research -"

"DR. ALPHYS'S FANFICTIONS NEVER INVOLVED ANY SKELETONS," Papyrus says. "NOT EVEN WHEN SOMEONE VERY ANONYMOUSLY REQUESTED IT. SHE INSISTS BONE ISN'T AS SEXY AS SCALES... OR FUR." He thinks for a moment. "I SHOULD SEND HER MORE PICTURES."

Oh stars. He's seen the kind of entertainment Alphys spends her time with. His magazines get creative. Alphys's stuff gets... wild. "...not exactly sure if that'd be the best source, bro."

"REALLY?" Papyrus rubs his jaw. "BUT SHE ALWAYS GOES INTO SUCH DETAIL..."

"Dr. Alphys is not a skeleton monster herself. All her knowledge would be secondhand," Gaster cuts in. "And as I've taught the both of you, always -"

"GO FOR A PRIMARY SOURCE!" Papyrus beams. "RIGHT?"

"Exactly."

Sans doesn't much care for Gaster's indulgent smile. It's a bit too keen, a bit too mellow - bit too tangled up in the way Papyrus's shirt still barely brushes the tops of his thighs. He snorts.

"and in this case the primary source would be... you?"

Gaster looks at him, long and level. Then - then his eyes narrow, but it's not tension, no - his gaze goes all half-lidded, slow and measuring. Heavy.

"Or you."

...maybe Papyrus has been right, all along, Sans realizes. Maybe his room could use some airing out, sometime. He's never before noticed how awful stuffy it can get. How warm. 

"It was quite rude of me to interrupt the two of you, wasn't it?" Gaster continues. "Just keep going as you were." He settles in to lean against the doorway. "Don't mind me."

Sans has to try again twice before any words come out. And the way Papyrus keeps fidgeting beside him... it sure doesn't help any. "not - not sure we particularly crave an audience."

"I -"

"I DON'T MIND!" Papyrus blushes under their collective gazes and draws in a deep breath. He turns to Sans. "BESIDES, IT WOULD BE ONLY FAIR. YOU WERE THE ONE SPYING ON US EARLIER!"

Sans splutters. "spying? no way. i just got ...caught off guard, is all. i wasn't expecting -"

"I did have your brother call you. I thought it was quite... self-evident, what was in process."

"hearing ain't seeing." And even with the warning it'd been less being taken off guard and more a slam dunk. Wasn't a thing that could've truly prepared him. "besides, looked to me like the two of you were mighty occupied. wouldn't have wanted to interfere."

"How considerate."

Sans wills the rising heat on his cheeks to fuck off. That smug, wry tone -

Papyrus makes a soft sound, almost like a sigh. Sans glances at him. His eyelights go out.

It appears Papyrus got frustrated with all the talking.

He's snuck a hand down between his thighs, slid it underneath the hem of his shirt, and while Sans can't see the exact details what he can see is that there's some definite… movement... going on in there. A whole lotta back and forth -

If there's an opposite to blue magic, Sans reckons he's now got firsthand experience.  Things going way up, way sudden, and leaving behind only a sweep of dizziness.

"pap, uh... what are you..."

Papyrus stills his hand and looks away, red and unhappy. "I'M SORRY, I JUST... IT FEELS SO UNBEARABLY HOT AGAIN... IT GOT BETTER FOR A WHILE, BUT NOW... IT'S - IT'S OVERWHELMING, LIKE I'M ALL ITCHY INSIDE.. I..." He twists the stained sheet between fingers. "I - I JUST NEED SOMETHING INSIDE ME AGAIN..."

Sans growls. 

There's a high-pitched squawk as Papyrus goes down onto the mattress. His mouth is still open in surprise when Sans climbs atop him and pins him down, and Sans wastes no time in capitalizing on that. His mouth is on Papyrus's, and their chests press together, and Sans is madly tearing at Papyrus's shirt to get it off, get it outta the way, and he's moving down and biting into Papyrus's neck and his shoulder and collarbone. Papyrus is moaning and calling his name, somewhere through the haze -

"Sans. Stop."

Sans freezes. Maybe it's the tone, maybe the actual blue magic sternly engulfing his soul.

When he continues, Gaster's voice is back to perfect calm. "You're being much too rough," he says. “You've never actually done this before, have you? The fumbling around speaks for itself."

He got interrupted just because Gaster felt the need to evaluate his performance?! Sans grinds his teeth together. It's an ugly sound. Papyrus trembles beneath him.

"says the guy who actually managed to find a way to procreate with mr. right hand and mr. left hand."

He's glad to note that Gaster doesn't seem particularly taken by the observation.

"I fail to see the relevance. Besides, I have done a considerable amount of research -"

_ "so have i _ ."

Papyrus is looking between them, as much as he can, pushed down onto the mattress with Sans blocking most of his view. "I HAD NO IDEA THIS WOULD BE A COMPETITION! OR I WOULD'VE PREPARED AS WELL!"

Gaster sighs. "It's not. Rather - it's not supposed to be."

At last he moves from his spot by the door. Usually the carpeted floor works to muffle any footsteps, but even without looking Sans can hear his steady approach as he walks towards the bed. He’s not looking because he’s both captured by Papyrus’s hopeful smile, and thinking about Gaster’s words. 

"Let me show you?"

Gaster's waiting, steady and composed and exactly like the crazy-brilliant larger-than-life monster Sans can hazily recall. The one he'd thought gone forever. The one he'd given up on. The one who's here, now, regardless.

Sans hesitates. 

Then he nods.

  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  



End file.
